Humidity is an intangible. You can’t see it or touch it. It has no color, sound, or odor. Therefore, it may be the least understood aspect of comfort conditioning.

To humidify is to artificially add moisture to the air. Humidity is the water vapor mixed in the air. Relative humidity is the amount of moisture in the air versus the amount that the air is capable of holding.

As air becomes colder, its ability to hold vapor decreases.

What are the benefits of proper humidification? They are comfort, preservation, and health.


Personal comfort is well known and understood by all of us. It encompasses warmth, thirst, skin tones, static electric shocks, stuffiness, parched throats, chapped lips, and hands.

Ask your customers if they are affected by any of these conditions during the heating season. Chances are, they probably haven’t considered that a humidifier can resolve these problems.

Moreover, when the home is properly humidified, customers’ thermostats may be set at a lower temperature and they will still feel comfortable, thus saving on their heating bill. There is a distinct comfort in that!

All animals are more comfortable when they live in proper humidity levels. Let your customers know that they can enjoy springtime freshness all winter when moisture is added to the air.


Preservation of valuable furniture, especially antiques and musical instruments, is highly desirable.

In addition, customers want to preserve woodwork in their homes, as well as veneers, plaster walls, tightness of windows and doors, carpets, and plants.

Ask your customers if they notice a change in how well their wooden doors open and shut during the heating season. Become familiar with the appearance of overly dry wood, and take a look around the customer’s house. Point out dry wood conditions to customers, and let them know that proper humidification can help protect their belongings.

Also, if they have expensive wooden musical instruments (pianos and just about any acoustic string instrument), ask if the instrument tends to go out of tune from season to season.

In addition to preventing the instrument’s soundboard from warping or splitting — which destroys the instrument’s value — consistent temperature and humidity levels help the instrument stay better in tune.

This is all very desirable and attainable when we add needed moisture with a whole-house, central-system humidifier mounted on the furnace.


Health benefits cannot be quantified. However, we know that doctors recommend humidification to reduce respiratory discomfort and dry skin problems. That’s one reason why they recommend drinking so much water per day.

(Note: Research is available showing the relative humidity levels at which germs and bacteria are most readily picked up by humans. Typically, extremely low and extremely high rh levels are the most “germ friendly.”)

When they express their interest, make sure you offer your customers a good humidifier.

Humidifier Types

It must be constructed of corrosion-resistant materials. It must also be easy to install and service with no tools required.

The humidifier should have automatic, or positive humidity and water control. It should introduce only pure water vapor into the home’s air. If it is a 120-V unit, UL listing should be required.

In a rotating-media pad system, the media pad rotates through a reservoir of water. The hot air from the furnace is forced through the pad, evaporating the water and introducing water vapor into the airflow.

It is important to note that with this type, no water is wasted. No drain is required unless local codes dictate otherwise.

With a fixed-pad humidifier, water is dripped through a stationary pad and a portion of the water is evaporated by the hot furnace air and goes into the home in the form of humidity. The remaining water goes down the drain.

The fixed-pad humidifier will cost more to operate, especially where water is an expensive utility and when you pay for both incoming and outgoing water. It also requires either a drain or a recirculating pump. But it also requires low maintenance.

The question you need the customer to answer is, “Do you want a rotating-pad type that requires occasional cleaning but does not waste water, or do you prefer a more costly unit to operate with less maintenance?”

Other options include self-contained humidifiers with remote-mount possibilities, units that do not require drains, humidifiers that are small in size to fit closet applications, and ones that will humidify small- to large-square-footage homes.

Give your customers a choice. After all, they pay the bills.

Barbara Worth is general manager for Lau Industries, a manufacturer of several models of humidifiers. You may reach her at 937-253-200; lau.conaire (e-mail).

Sidebar: Humidification-dehumidification information for your customers

The drying effects of home heating are constantly at work in the winter. For the sake of comfort and health, an indoor relative humidity level of between 30% to 50% is recommended.

As outdoor temperatures drop, humidity levels indoors should be lowered. The humidity is right for you when the room feels “comfortable.”

Signs of low humidity include static electricity, a physically uncomfortable dry feeling, plants that wither and die, and a cold feeling even though the room temperature is relatively high.

Cleaning humidifiers

First and foremost, follow the manufacturer’s instructions on how to clean its particular brand of humidifier.

As air passes through the pad, some particles of dirt are trapped; also, the pad may become heavy with hard water particles, which collect on the fibers of the pad as the water evaporates. And even if the interior liner and other functional parts are made of non-corrosive materials, rust can result from iron in the water.

The following tips can be passed on to your customers as a service. Keep in mind that some customers may prefer that their contractor take care of this, offering an opportunity for service contracts.

  •  It is important to clean the humidifier regularly to remove lime scale caused by water minerals, which collect on the belts, the water reservoir, and other parts that come in contact with the water.

  •  The pad, liner, and other interior parts need to be cleaned frequently. Be careful when putting parts back together so no malfunction will occur.

  •  Regular use of a liquid water conditioner solution will help control odor and simplify cleaning. Some units have dispensers that store and then dispense the solution directly into the reservoir water.

  •  Some humidifiers have drain outlets; others need to be operated until all water is removed before cleaning.

  •  Cleaning of the humidifier outdoors or in the basement with the use of a hose may make it unnecessary to take the pad off the holder, but there is the possibility that water may get into the motor or controls.

  •  Plastic parts may be damaged if hot water is used to fill the tank. Pads may wear out or become ineffective. Once-a-year replacement may be warranted.

  •  Between operations, the unit should not be stored or left for long periods with water in it. Undesirable odors from the growth of fungus and bacteria may develop.


    If your customers frequently smell musty odors or feel damp spots on the floors or walls of their basement, laundry room, or storage area during warm, humid weather, they need a dehumidifier.

    The recommended humidity level inside the home during summer is around 40% to 50%. Overly humid conditions over an extended period can leave occupants uncomfortable and can damage the home.

    Musty smells, peeling wallpaper, warped wood, rusting tools, blistered paint, and moisture dripping from pipes are signs of excessive humidity. These conditions are most common during spring and summer.

    Dehumidifiers remove excess humidity by drawing moist room air over cold refrigerated coils. The moisture in the air condenses into droplets as it passes over the cold surfaces in the dehumidifier and into a container.

    Drier air then returns to the room at approximately its original temperature. For best results, the unit should be located in an area closed off from outdoor air, and where air movement in and out of the unit is not restricted.

    This information came from the Michigan State University Extension’s report #01500033, “Home Maintenance and Repair.”